Multicast Distribution of Incrementally Enhanced Content

ABSTRACT

A client system includes a processor configured to obtain multicast information for a content item, the multicast information including information about a multicast session for a base stream and additional multicast sessions for available incremental streams. The processor is also configured to determine an available bandwidth, and to join a set of initial multicast sessions based on the available bandwidth, the set of initial multicast sessions including the multicast session for the base stream and at least one of the additional multicast sessions for the incremental streams. The processor is also configured to monitor a network condition, and to perform an action based on the network condition, the action selected from the group consisting of joining another of the additional multicast sessions, leaving one of the initial multicast sessions, and a combination thereof.

FIELD OF THE DISCLOSURE

The present disclosure generally relates to communications networks, andmore particularly relates to multicast distribution of incrementallyenhanced content.

BACKGROUND

A television service provider can transmit a television signal, such asthrough an Internet Protocol Television (IPTV) network or a cablenetwork, to a user. The television service provider can offer the user avariety of different content and services. For example, the televisionservice provider can supply users with real-time television programsthat are typically available for the users to watch only at a specificdate and time. The user may record the real-time television programs,such as with a digital video recorder (DVR), so that the programs can beviewed at a time of the user's choosing.

The television service provider can also offer the users on-demandcontent that is available for an extended amount of time. The on-demandcontent can allow a user to view a program at a time of their choosingand can be provided to the user upon request. On-demand content can bestreamed from a server across the network for display on a TV in thehome, or on-demand content can be downloaded to a storage device in thehome and then displayed on a TV or streamed over the home network to aTV.

BRIEF DESCRIPTION OF THE DRAWINGS

It will be appreciated that for simplicity and clarity of illustration,elements illustrated in the Figures have not necessarily been drawn toscale. For example, the dimensions of some of the elements areexaggerated relative to other elements. Embodiments incorporatingteachings of the present disclosure are shown and described with respectto the drawings presented herein, in which:

FIG. 1 is a block diagram illustrating an Internet Protocol Television(IPTV) network in accordance with one embodiment of the presentdisclosure;

FIG. 2 is a block diagram illustrating a communications network inaccordance with one embodiment of the present disclosure;

FIG. 3 is a block diagram illustrating a system for delivery of contentin accordance with one embodiment of the present disclosure;

FIG. 4 is a flow diagram illustrating an exemplary method of deliveringcontent in accordance with one embodiment of the present disclosure; and

FIG. 5 is an illustrative embodiment of a general computer system.

The use of the same reference symbols in different drawings indicatessimilar or identical items.

DETAILED DESCRIPTION OF THE DRAWINGS

The numerous innovative teachings of the present application will bedescribed with particular reference to the presently preferred exemplaryembodiments. However, it should be understood that this class ofembodiments provides only a few examples of the many advantageous usesof the innovative teachings herein. In general, statements made in thespecification of the present application do not necessarily limit any ofthe various claimed inventions. Moreover, some statements may apply tosome inventive features but not to others.

FIG. 1 shows an IPTV system 100 including a client facing tier 102, anapplication tier 104, an acquisition tier 106, and an operations andmanagement tier 108. Each tier 102, 104, 106, and 108 is coupled to oneor both of a private network 110 and a public network 112. For example,the client-facing tier 102 can be coupled to the private network 110,while the application tier 104 can be coupled to the private network 110and to the public network 112 such as the Internet. The acquisition tier106 can also be coupled to the private network 110 and to the publicnetwork 112. Moreover, the operations and management tier 108 can becoupled to the public network 112.

The various tiers 102, 104, 106, and 108 communicate with each other viathe private network 110 and the public network 112. For instance, theclient-facing tier 102 can communicate with the application tier 104 andthe acquisition tier 106 via the private network 110. The applicationtier 104 can also communicate with the acquisition tier 106 via theprivate network 110. Further, the application tier 104 can communicatewith the acquisition tier 106 and the operations and management tier 108via the public network 112. Moreover, the acquisition tier 106 cancommunicate with the operations and management tier 108 via the publicnetwork 112. In a particular embodiment, elements of the applicationtier 104 can communicate directly with the client-facing tier 102.

The client-facing tier 102 can communicate with user equipment via aprivate access network 166, such as an Internet Protocol Television(IPTV) network. In an illustrative embodiment, residential gateways(RGs) such as a first RG 114 and a second RG 122 can be coupled to theprivate access network 166. The client-facing tier 102 can communicatewith a first representative set-top box device 116 via the first RG 114and with a second representative set-top box device 124 via the secondRG 122. The client-facing tier 102 can communicate with a large numberof set-top boxes over a wide geographic area, such as a regional area, ametropolitan area, a viewing area, or any other suitable geographic areathat can be supported by networking the client-facing tier 102 tonumerous set-top box devices. In one embodiment, the client-facing tier102 can be coupled to the RGs 114 and 122 via fiber optic cables.Alternatively, the RGs 114 and 122 can be digital subscriber line (DSL)RGs that are coupled to one or more network nodes via twisted pairs, andthe client-facing tier 102 can be coupled to the network nodes viafiber-optic cables. Each set-top box device 116 and 124 can process datareceived from the private access network 166 via an IPTV softwareplatform such as Microsoft® TV IPTV Edition.

The first set-top box device 116 can be coupled to a first displaydevice 118, such as a first television monitor, and the second set-topbox device 124 can be coupled to a second display device 126, such as asecond television monitor. Moreover, the first set-top box device 116can communicate with a first remote control 120, and the second set-topbox device 124 can communicate with a second remote control 128. In anexemplary, non-limiting embodiment, each set-top box device 116 and 124can receive data or video from the client-facing tier 102 via theprivate access network 166 and render or display the data or video atthe display device 118 or 126 to which it is coupled. The set-top boxdevices 116 and 124 thus may include tuners that receive and decodetelevision programming information for transmission to the displaydevices 118 and 126. Further, the set-top box devices 116 and 124 caninclude a set-top box processor 170 and a set-top box memory device 172that is accessible to the set-top box processor. In a particularembodiment, the set-top box devices 116 and 124 can also communicatecommands received from the remote controls 120 and 128 back to theclient-facing tier 102 via the private access network 166.

In an illustrative embodiment, the client-facing tier 102 can include aclient-facing tier (CFT) switch 130 that manages communication betweenthe client-facing tier 102 and the private access network 166 andbetween the client-facing tier 102 and the private network 110. Asshown, the CFT switch 130 is coupled to one or more data servers 132that store data transmitted in response to user requests, such asvideo-on-demand material. The CFT switch 130 can also be coupled to aterminal server 134 that provides terminal devices, such as a gameapplication server and other devices with a common connection point tothe private network 110. In a particular embodiment, the CFT switch 130can also be coupled to a video-on-demand (VOD) server 136.

The application tier 104 can communicate with both the private network110 and the public network 112. In this embodiment, the application tier104 can include a first application tier (APP) switch 138 and a secondAPP switch 140. In a particular embodiment, the first APP switch 138 canbe coupled to the second APP switch 140. The first APP switch 138 can becoupled to an application server 142 and to an operation systems andsupport/billing systems and support (OSS/BSS) gateway 144. Theapplication server 142 provides applications to the set-top box devices116 and 124 via the private access network 166, so the set-top boxdevices 116 and 124 can provide functions such as display, messaging,processing of IPTV data and VOD material. In a particular embodiment,the OSS/BSS gateway 144 includes OSS data, as well as BSS data.

The second APP switch 140 can be coupled to a domain controller 146 thatprovides web access, for example, to users via the public network 112.The second APP switch 140 can be coupled to a subscriber and systemstore 148 that includes account information, such as account informationthat is associated with users who access the system 100 via the privatenetwork 110 or the public network 112. In a particular embodiment, theapplication tier 104 can also include a client gateway 150 thatcommunicates data directly to the client-facing tier 102. In thisembodiment, the client gateway 150 can be coupled directly to the CFTswitch 130. The client gateway 150 can provide user access to theprivate network 110 and the tiers coupled thereto.

In a particular embodiment, the set-top box devices 116 and 124 canaccess the system via the private access network 166 using informationreceived from the client gateway 150. The private access network 166provides security for the private network 110. User devices can accessthe client gateway 150 via the private access network 166, and theclient gateway 150 can allow such devices to access the private network110 once the devices are authenticated or verified. Similarly, theclient gateway 150 can prevent unauthorized devices, such as hackercomputers or stolen set-top box devices, from accessing the privatenetwork 110 by denying access to these devices beyond the private accessnetwork 166.

For example, when the set-top box device 116 accesses the system 100 viathe private access network 166, the client gateway 150 can verifysubscriber information by communicating with the subscriber and systemstore 148 via the private network 110, the first APP switch 138 and thesecond APP switch 140. Further, the client gateway 150 can verifybilling information and status by communicating with the OSS/BSS gateway144 via the private network 110 and the first APP switch 138. TheOSS/BSS gateway 144 can transmit a query across the first APP switch138, to the second APP switch 140, and the second APP switch 140 cancommunicate the query across the public network 112 to the OSS/BSSserver 164. After the client gateway 150 confirms subscriber and/orbilling information, the client gateway 150 can allow the first set-topbox device 116 access to IPTV content and VOD content. If the clientgateway 150 cannot verify subscriber information for the first set-topbox device 116, such as because it is connected to a different twistedpair, the client gateway 150 can deny transmissions to and from thefirst set-top box device 116 beyond the private access network 166.

The acquisition tier 106 includes an acquisition tier (AQT) switch 152that communicates with the private network 110. The AQT switch 152 canalso communicate with the operations and management tier 108 via thepublic network 112. In a particular embodiment, the AQT switch 152 canbe coupled to a live acquisition server 154 that receives televisioncontent, for example, from a broadcast service 156. Further, the AQTswitch can be coupled to a video-on-demand importer server 158 thatstores television content received at the acquisition tier 106 andcommunicate the stored content to the client-facing tier 102 via theprivate network 110.

The operations and management tier 108 can include an operations andmanagement tier (OMT) switch 160 that conducts communication between theoperations and management tier 108 and the public network 112. In theillustrated embodiment, the OMT switch 160 is coupled to a TV2 server162. Additionally, the OMT switch 160 can be coupled to an OSS/BSSserver 164 and to a simple network management protocol (SNMP) monitor170 that monitors network devices. In a particular embodiment, the OMTswitch 160 can communicate with the AQT switch 152 via the publicnetwork 112.

In a particular embodiment during operation of the IPTV system, the liveacquisition server 154 can acquire television content from the broadcastservice 156. The live acquisition server 154 in turn can transmit thetelevision content to the AQT switch 152 and the AQT switch can transmitthe television content to the CFT switch 130 via the private network110. Further, the television content can be encoded at the D-servers132, and the CFT switch 130 can communicate the television content tothe RGs 114 and 122 via the private access network 166. The set-top boxdevices 116 and 124 can receive the television content from the RGs 114and 122, decode the television content, and transmit the content to thedisplay devices 118 and 126 according to commands from the remotecontrol devices 120 and 128.

Additionally, at the acquisition tier 106, the VOD importer server 158can receive content from one or more VOD sources outside the IPTV system100, such as movie studios and programmers of non-live content. The VODimporter server 158 can transmit the VOD content to the AQT switch 152,and the AQT switch 152 in turn can communicate the material to the CFTswitch 130 via the private network 110. The VOD content can be stored atone or more servers, such as the VOD server 136.

When a user issues a request for VOD content to the set-top box device116 or 124, the request can be transmitted over the private accessnetwork 166 to the VOD server 136 via the CFT switch 130. Upon receivingsuch a request, the VOD server 136 can retrieve requested VOD contentand transmit the content to the set-top box device 116 or 124 across theprivate access network 166 via the CFT switch 130. In an illustrativeembodiment, the live acquisition server 154 can transmit the televisioncontent to the AQT switch 152, and the AQT switch 152 in turn cantransmit the television content to the OMT switch 160 via the publicnetwork 112. In this embodiment, the OMT switch 160 can transmit thetelevision content to the TV2 server 162 for display to users accessingthe user interface at the TV2 server. For example, a user can access theTV2 server 162 using a personal computer (PC) 168 coupled to the publicnetwork 112.

The domain controller 146 communicates with the public network 112 viathe second APP switch 140. Additionally, the domain controller 146 cancommunicate via the public network 112 with the PC 168. For example, thedomain controller 146 can display a web portal via the public network112 and allow users to access the web portal using the PC 168. Further,in an illustrative embodiment, the domain controller 146 can communicatewith at least one wireless network access point 178 over a data network176. In this embodiment, each wireless network access point 178 cancommunicate with user wireless devices such as a cellular telephone 184.

In a particular embodiment, the set-top box devices can include aset-top box computer program 174 that is embedded within the set-top boxmemory device 172. The set-top box computer program 174 can containinstructions to receive and execute at least one user television viewingpreference that a user has entered by accessing an Internet user accountvia the domain controller 146. For example, the user can use the PC 168to access a web portal maintained by the domain controller 146 via theInternet. The domain controller 146 can query the subscriber and systemstore 148 via the private network 110 for account information associatedwith the user. In a particular embodiment, the account information canassociate the user's Internet account with the second set-top box device124. For instance, in an illustrative embodiment, the accountinformation can relate the user's account to the second set-top boxdevice 124 by associating the user account with an IP address of thesecond set-top box device, with data relating to one or more twistedpairs connected with the second set-top box device, with data related toone or more fiber optic cables connected with the second set-top boxdevice, with an alphanumeric identifier of the second set-top boxdevice, with any other data that is suitable for associating secondset-top box device with a user account, or with any combination ofthese.

FIG. 2 shows a multicast tree 200 for distributing digital contentthrough a geographically dispersed network, such as the Internet.Multicast tree 200 can include a server 202 and client devices 204, 206,208, 210, 212, 214, 216, and 218. Server 202 and client devices 204,206, 208, 210, 212, 214, 216, and 218 can communicate through a networkof distribution points 220, 224, 226, 228, and 230. The distributionpoints 220, 224, 226, 228, and 230 may be routers. Alternatively, thedistribution points 220, 224, 226, 228, and 230 may be nodes of anoverlay network. For example, communications from server 202 can travelthrough distribution points 220, 224, and 226 to client device 208 whilecommunications from server 202 can travel through distribution points220 and 230 to client 216. It will be appreciated that multicast tree200 may be a logical overlay of a mesh network that, for example, mayhave a direct connection from distribution point 230 to 228, and also,for example, may have a direct connection from distribution point 226 to230. These distribution points may be multicast-enabled routers. Thedistribution points may have the ability to cache content not only forimmediate forwarding but also for later retransmission.

Server 202 can use Internet Protocol (IP) multicast or any othermulticast protocol to substantially simultaneously distribute digitalcontent to the client devices 204, 206, 208, 210, 212, 214, 216, and218. The digital content can be divided into multiple segments or datapackets that may be, but are not necessarily IP packets, Ethernetframes, or similar lower layer packets. Using a multicast protocol, eachsuch segment or data packet can move over each link of the network onlyonce. The distribution points 220, 224, 226, 228, and 230 can createcopies, or otherwise forward incoming data on one port to multipleoutbound ports, when the paths to the destinations split. For example,server 202 can send a multicast data packet to distribution point 220.Distribution point 220 can send a copy of the data packet to each ofclient 204, distribution point 224, and distribution point 230.Similarly, distribution point 230 can send, forward, or route a copy ofthe segment, data packet, or individual low layer packets to each ofclient devices 216 and 218, and distribution point 224 can send a copyof the data packet to each of distribution points 226 and 228. Further,distribution point 226 can send a copy of the data packet to each ofclient devices 206 and 208, and distribution point 228 can send a copyof the data packet to each of client devices 210, 212, and 214. In otherembodiments, the network underlying multicast tree 200 may be a sharedmedium, such as a bus or ring, with multicast occurring at a low networklayer via common physical components and a common media accessstructure.

Generally, the distribution points construct or join the multicast tree200 when client devices join a multicast group, and the server 202 maynot have information about each member of the multicast group.Specifically, client devices can notify the network that they areinterested in receiving data packets sent to the multicast group, suchas by Internet Group Management Protocol. The server 202 can send amessage addressed to the multicast group and each distribution point canreplicate the data packet for each system of the multicast group.

FIG. 3 illustrates an exemplary system 300 for delivery of content 302.The content 302 can be video content, audio content, or any combinationthereof. The content can include broadcast content, on-demand content,or any combination thereof. The content can include a series of framesat a maximum resolution, represented by the bars 306. The content can beencoded by an encoder 304 into content streams 308, 310, 312, and 314.The encoder can use an incremental layer encoding algorithm to generatemultiple lower bandwidth streams that can be added together to obtainthe content in various resolutions depending on the number of streamsthat are combined. Streams 308, 310, 312, and 314 can include a basestream 308 and a plurality of incremental streams 310, 312, and 314. Theincremental streams 310, 312, and 314 can be added to the base stream308 to provide a higher resolution stream, as illustrated by blocks B,1, 2, and 3 of bars 316.

Streams 308, 310, 312, and 314 can be delivered to the network 318 inmulticast sessions 320, 322, 324, and 326. Multicast session 320 candeliver the base stream, multicast session 322 can deliver the firstincremental stream, multicast session 324 can deliver the secondincremental stream, and multicast session 326 can deliver the thirdincremental stream.

Client devices 328, 330, and 332 can each receive one or more of themulticast streams to obtain the content. The number of multicastsessions received by each of client devices 328, 330, and 332 can dependon the available bandwidth for the client device, the maximum resolutiondisplayable by the client device, the resolution that has beensubscribed to or purchased, or any combination thereof.

For example, client device 328 may be restricted from receiving thethird incremental stream based on the subscribed resolution. That is,client device 328 may be subscribed to a standard definition televisionpackage and may be restricted from receiving high-definition content.Moreover, client device 328 may have an initial available bandwidthsufficient for only two of the multicast sessions. As such, clientdevice 328 can initially receive multicast sessions 320 and 322. At timepoint 334, additional bandwidth may become available for client device328 to begin to receive multicast session 324 to obtain the content 302at a higher resolution than was previously displayed.

In another example, client device 330 may be limited to displaying aresolution provided by the base stream, and therefore may be limited toreceiving only the base stream. For example, client device 330 may be amobile device with a limited resolution display.

In yet another example, client device 332 may be able to receive thecontent at the maximum resolution, and may initially join multicastsessions 320, 322, 324, and 326. However, at time point 336, networkconditions may limit the amount of available bandwidth for client device332. For example, a rate of dropped packets or a network latency mayexceed a threshold, or other applications may require a portion of thenetwork bandwidth available to client device 332. As such, client device332 may leave multicast session 326 and only receive the base stream andthe first and second incremental streams. Thus, client device 332 mayprovide a lower resolution display of the content after time point 336.

FIG. 4 illustrates a method for multicast distribution of incrementallyenhanced content. At 402, the server receives content, such as audiocontent, video content, or any combination thereof. The content can bebroadcast content, on-demand content, or any combination thereof. At404, the server can encode the content using an incremental layerencoding algorithm. The incremental layer encoding algorithm cangenerate a low resolution base stream and multiple incremental streams.The incremental streams can encode additionally information such thatwhen combined with the base stream, the combination of the base streamand the incremental streams can provide higher resolution content thatprovided by the base stream alone.

For example, the base stream can provide a low resolution streamsuitable for playback on a portable device, such as a resolution of480×320 pixels. Additionally, a first incremental stream, when combinedwith the base stream, can provide a standard definition televisionstream, such as a resolution of 720 by 480 pixels, while a secondincremental stream, when combined with the base stream and the firstincremental stream, can provide a high definition television stream,such as a 720 p (approximately 1280×720 pixels) video stream. Further, athird incremental stream, when combined with the other streams canprovide a 1080 p (approximately 1920×1080 pixels) video stream.

At 406, the server can establish multiple concurrent multicast sessionsto provide the content streams. Each multicast session can provide oneof the base stream or incremental streams to client devices joined tothe multicast session. The client devices may receive information aboutjoining the multicast sessions and can select one or more of themulticast sessions based on network conditions and other factors.

At 408, a client device can determine an initial available bandwidth forreceiving the content. For example, the client device can track anaverage total bandwidth and determine the bandwidth currently in use byother network applications, such as other content streams, use of theInternet, voice-over-IP streams, and the like. The initial availablebandwidth can be determined from the difference between the averagetotal bandwidth and the currently used bandwidth.

At 410, the client device can join a subset of the multicast sessionsprovided by the server to deliver the content. Specifically, the clientdevice can send a request for the content and can receive informationfor joining the multicast sessions. Additionally, the client device candetermine the number of streams that can be received within theinitially available bandwidth. The client device can then join themulticast sessions to receive the base stream and, optionally, one ormore incremental streams. If the initially available bandwidth is notsufficient to receive the base stream, the client device can notify theuser that the content is unavailable.

In an embodiment, the client device may be limited to the number ofavailable incremental streams. For example, a client device subscribedto standard definition content may be restricted from accessingincremental streams that can provide high definition content, but canhave access to all incremental streams necessary to provide the maximumresolution standard definition content. Similarly, for purchases ofstandard definition content, client devices may be restricted fromaccessing the incremental streams necessary to provide the content inhigh definition. In another example, a client device may be a devicewith a limited resolution, such as a mobile device. The number ofavailable incremental streams may be limited based on the screenresolution of the device. The restriction can be implemented by theserver providing the client device with only the information necessaryto receive the accessible streams and withholding information forjoining the multicast sessions to receive the prohibited stream.Alternatively, the restriction can be implemented by the client device.For example, the client device may receive the information necessary tojoin all of the multicast sessions for the content, but may beconfigured to join only the multicast sessions for the allowablestreams.

At 412, the client device can combine and decode the base stream and theoptional incremental streams to obtain the content at a first availableresolution. In an embodiment, the first available resolution can be lessthan the resolution of the device or the maximum allowable resolution,such as based on the purchased or subscribed content, due to limitationsin the available bandwidth.

At 414, the client device can monitor a network condition, such as anetwork latency, a number of dropped packets, a currently usedbandwidth, or any combination thereof. At 416, the client device candetermine if there is insufficient bandwidth. At 418, when the clientdevice determines there is insufficient bandwidth, such as when thenumber of dropped packets, network latency, or currently used bandwidthexceed a threshold, the client device can leave one of the multicastsessions. For example the client device can leave the multicast sessionproviding the highest incremental stream.

Alternatively, at 420, when there is not insufficient bandwidth, such aswhen the network latency or the number of dropped packets is below athreshold, the client device can determine if there is additionalavailable bandwidth. At 422, when there is additional availablebandwidth, such as when the currently used bandwidth, the networklatency, and the number of dropped packets are below a threshold, theclient system can join an additional multicast session to receive anadditional incremental stream. The additional incremental stream can beused by the client device to provide higher resolution content than waspreviously received. Thus, the client device can dynamically change theresolution of the content based on the current network conditions. In anembodiment, the client device can only join an additional multicastsession when an additional multicast session is available such as whenthe client device is currently receiving content below an allowableresolution. Alternatively, returning to 420, when additional bandwidthis not available, the client device can continue to monitor the networkcondition at 414.

FIG. 5 shows an illustrative embodiment of a general computer system500. The computer system 500 can include a set of instructions that canbe executed to cause the computer system to perform any one or more ofthe methods or computer based functions disclosed herein. The computersystem 500 may operate as a standalone device or may be connected, suchas by using a network, to other computer systems or peripheral devices.Examples of the general computer system can include set-top box 124,server 202, distribution point 220, client system 210, and the like.

In a networked deployment, the computer system may operate in thecapacity of a server or as a client user computer in a server-clientuser network environment, or as a peer computer system in a peer-to-peer(or distributed) network environment. The computer system 500 can alsobe implemented as or incorporated into various devices, such as apersonal computer (PC), a tablet PC, an STB, a personal digitalassistant (PDA), a mobile device, a palmtop computer, a laptop computer,a desktop computer, a communications device, a wireless telephone, aland-line telephone, a control system, a camera, a scanner, a facsimilemachine, a printer, a pager, a personal trusted device, a web appliance,a network router, switch or bridge, or any other machine capable ofexecuting a set of instructions (sequential or otherwise) that specifyactions to be taken by that machine. In a particular embodiment, thecomputer system 500 can be implemented using electronic devices thatprovide voice, video or data communication. Further, while a singlecomputer system 500 is illustrated, the term “system” shall also betaken to include any collection of systems or sub-systems thatindividually or jointly execute a set, or multiple sets, of instructionsto perform one or more computer functions.

The computer system 500 may include a processor 502, such as a centralprocessing unit (CPU), a graphics processing unit (GPU), or both.Moreover, the computer system 500 can include a main memory 504 and astatic memory 506 that can communicate with each other via a bus 508. Asshown, the computer system 500 may further include a video display unit510 such as a liquid crystal display (LCD), an organic light emittingdiode (OLED), a flat panel display, a solid-state display, or a cathoderay tube (CRT). Additionally, the computer system 500 may include aninput device 512 such as a keyboard, and a cursor control device 514such as a mouse. Alternatively, input device 512 and cursor controldevice 514 can be combined in a touchpad or touch sensitive screen. Thecomputer system 500 can also include a disk drive unit 516, a signalgeneration device 518 such as a speaker or remote control, and a networkinterface device 520 to communicate with a network 526. In a particularembodiment, the disk drive unit 516 may include a computer-readablemedium 522 in which one or more sets of instructions 524, such assoftware, can be embedded. Further, the instructions 524 may embody oneor more of the methods or logic as described herein. In a particularembodiment, the instructions 524 may reside completely, or at leastpartially, within the main memory 504, the static memory 506, and/orwithin the processor 502 during execution by the computer system 500.The main memory 504 and the processor 502 also may includecomputer-readable media.

The illustrations of the embodiments described herein are intended toprovide a general understanding of the structure of the variousembodiments. The illustrations are not intended to serve as a completedescription of all of the elements and features of apparatus and systemsthat utilize the structures or methods described herein. Many otherembodiments may be apparent to those of skill in the art upon reviewingthe disclosure. Other embodiments may be utilized and derived from thedisclosure, such that structural and logical substitutions and changesmay be made without departing from the scope of the disclosure.Additionally, the illustrations are merely representational and may notbe drawn to scale. Certain proportions within the illustrations may beexaggerated, while other proportions may be minimized. Accordingly, thedisclosure and the FIGs. are to be regarded as illustrative rather thanrestrictive.

The Abstract of the Disclosure is provided to comply with 37 C.F.R.§1.72(b) and is submitted with the understanding that it will not beused to interpret or limit the scope or meaning of the claims. Inaddition, in the foregoing Detailed Description of the Drawings, variousfeatures may be grouped together or described in a single embodiment forthe purpose of streamlining the disclosure. This disclosure is not to beinterpreted as reflecting an intention that the claimed embodimentsrequire more features than are expressly recited in each claim. Rather,as the following claims reflect, inventive subject matter may bedirected to less than all of the features of any of the disclosedembodiments. Thus, the following claims are incorporated into theDetailed Description of the Drawings, with each claim standing on itsown as defining separately claimed subject matter.

The above disclosed subject matter is to be considered illustrative, andnot restrictive, and the appended claims are intended to cover all suchmodifications, enhancements, and other embodiments which fall within thetrue spirit and scope of the present disclosed subject matter. Thus, tothe maximum extent allowed by law, the scope of the present disclosedsubject matter is to be determined by the broadest permissibleinterpretation of the following claims and their equivalents, and shallnot be restricted or limited by the foregoing detailed description.

1. A client device comprising: a processor configured to: obtainmulticast information for a content item, the multicast informationincluding information about a multicast session for a base stream andadditional multicast sessions for available incremental streams;determine an available bandwidth; join a set of initial multicastsessions based on the available bandwidth, the set of initial multicastsessions including the multicast session for the base stream and atleast one of the additional multicast sessions for the incrementalstreams; monitor a network condition; and perform an action based on thenetwork condition, the action selected from the group consisting ofjoining another of the additional multicast sessions, leaving one of theinitial multicast sessions, and a combination thereof.
 2. The clientdevice of claim 1, wherein the network condition includes one of a groupconsisting of a number of dropped packets, a number of out of orderpackets, a latency, and a combination thereof.
 3. The client device ofclaim 1, wherein the set of initial multicast sessions is further basedon a set of allowable incremental streams.
 4. The client device of claim3, further comprising determining the set of allowable incrementalstreams based on a service level of the client device.
 5. The clientdevice of claim 4, wherein the service level includes a maximumsubscribed resolution, and the set of allowable incremental streamscorresponds to the subset of incremental streams necessary for themaximum subscribed resolution.
 6. The client device of claim 4, whereinthe service level includes a maximum displayable resolution, and the setof allowable incremental streams corresponds to the subset ofincremental streams necessary for the maximum displayable resolution. 7.The client device of claim 4, wherein the service level includes amaximum purchased resolution, and the set of allowable incrementalstreams corresponds to the subset of incremental streams necessary forthe maximum purchased resolution.
 8. A non-transitory computer readablemedium comprising a plurality of instructions to manipulate a processor,the plurality of instructions comprising: instructions for obtainingmulticast information for a content item, the multicast informationincluding information about a multicast session for a base stream andadditional multicast sessions for available incremental streams;instructions for determining an available bandwidth; instructions forjoining a set of initial multicast sessions based on the availablebandwidth, the set of initial multicast sessions including the multicastsession for the base stream and at least one of the multicast sessionsfor the incremental streams; instructions for monitoring a networkcondition; and instructions for performing an action based on a changein the network condition, the action selected from the group consistingof joining another of the additional multicast sessions and leaving oneof the initial multicast sessions.
 9. The non-transitory computerreadable medium of claim 8, wherein the network condition includes oneof a group consisting of a number of dropped packets, a number of out oforder packets, a latency, and a combination thereof.
 10. Thenon-transitory computer readable medium of claim 8, further comprisinginstructions to determine a service level and a set of allowableincremental streams
 11. The non-transitory computer readable medium ofclaim 10, wherein the initial set of incremental streams is furtherbased on the set of allowable incremental streams
 12. The non-transitorycomputer readable medium of claim 8, wherein the available incrementalstreams are a subset of incremental streams based on a service level ofthe client
 13. The non-transitory computer readable medium of claim 12,wherein the service level includes a maximum subscribed resolution, andthe available incremental streams corresponds to the subset ofincremental streams necessary for the maximum subscribed resolution. 14.The non-transitory computer readable medium of claim 12, wherein theservice level includes a maximum displayable resolution, and theavailable incremental streams corresponds to the subset of incrementalstreams necessary for the maximum displayable resolution.
 15. Thenon-transitory computer readable medium of claim 12, wherein the servicelevel includes a maximum purchased resolution, and the availableincremental streams corresponds to the subset of incremental streamsnecessary for the maximum purchased resolution.
 16. A server comprising:a processor configured to: receive a request for content from a device;determine a service level for the device; determine availableincremental streams based in the service level, the availableincremental streams being a subset of incremental streams of anincremental layer encoded content, the incremental layer encoded contentincluding a base stream and the incremental streams; and providemulticast information to the device, the multicast information includinginformation about joining multicast sessions for the base stream and theavailable incremental streams.
 17. The server of claim 16, wherein theservice level includes a maximum subscribed resolution, and theavailable incremental streams corresponds to the subset of incrementalstreams necessary for the maximum subscribed resolution.
 18. The serverof claim 16, wherein the service level includes a maximum displayableresolution and the available incremental streams corresponds to thesubset of incremental streams necessary for the maximum displayableresolution.
 19. The server of claim 16, wherein the service levelincludes a maximum purchased resolution, and the available incrementalstreams corresponds to the subset of incremental streams necessary forthe maximum purchased resolution.